A Japanese study took the ancient concept of “shinrin-yoku,” (forest-air bathing and walking – wherein the subject “bathes” themselves in the forest air and elements) and measured “salivary amylase activity,” a measure of stress, and found that “the forest was a good environment in which people could experience much less environment-derived stress"  (Yamaguchi et al., 2006, p. 152).

In fact, the Japanese have an entire department dedicated to "Forest Medicine" at the Nippon Medical School established since "the  Ministry of Agriculture, Forestry and Fisheries of Japan initiated a research project between 2004 and 2006 to investigate the therapeutic effects of forests on human health from a scientific perspective. After 3 years, the project team has obtained a lot of results on forest medicine. The project team has found that forest bathing trips reduce the concentration of cortisol in saliva, reduce the concentrations of urinary adrenaline and noradrenaline, reduce prefrontal cerebral activity, reduce blood pressure and stabilize autonomic nervous activity in humans. Moreover, they found that visiting a forest, but not a city, increases human natural killer (NK) activity and the expression of anti-cancer proteins including perforin, granzymes A/B and granulysin, and that the increased NK activity and anti-cancer proteins lasted for more than 30 days after the trip."  Full details at: 

http://forest-medicine.com/epage04.php

Yamaguchi, M., Deguchi, M. & Miyazaki, Y.  (2006).  Sympathetic nervous activity in forest and urban environments.  Journal of International Medical Research, 34, 152-159.

A Japanese study took the ancient concept of “shinrin-yoku,” (forest-air bathing and walking – wherein the subject “bathes” themselves in the forest air and elements) and measured “salivary amylase activity,” a measure of stress, and found that “the forest was a good environment in which people could experience much less environment-derived stress"  (Yamaguchi et al., 2006, p. 152).

In fact, the Japanese have an entire department dedicated to "Forest Medicine" at the Nippon Medical School established since "the  Ministry of Agriculture, Forestry and Fisheries of Japan initiated a research project between 2004 and 2006 to investigate the therapeutic effects of forests on human health from a scientific perspective. After 3 years, the project team has obtained a lot of results on forest medicine. The project team has found that forest bathing trips reduce the concentration of cortisol in saliva, reduce the concentrations of urinary adrenaline and noradrenaline, reduce prefrontal cerebral activity, reduce blood pressure and stabilize autonomic nervous activity in humans. Moreover, they found that visiting a forest, but not a city, increases human natural killer (NK) activity and the expression of anti-cancer proteins including perforin, granzymes A/B and granulysin, and that the increased NK activity and anti-cancer proteins lasted for more than 30 days after the trip."  Full details at: 

http://forest-medicine.com/epage04.php

Yamaguchi, M., Deguchi, M. & Miyazaki, Y.  (2006).  Sympathetic nervous activity in forest and urban environments.  Journal of International Medical Research, 34, 152-159.